var http_request = false;


function makeRequest(url) {
	http_request = false;
	if (window.XMLHttpRequest) { // Mozilla, Safari,...
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/xml');
		}
	}
	else if (window.ActiveXObject) { // IE
		try {
				http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {try {http_request = new ActiveXObject("Microsoft.XMLHTTP");}
		catch (e) {}}
	}
	
	if (!http_request) {
		alert('Giving up :( Cannot create an XMLHTTP instance');
		return false;
	}
	
	http_request.onreadystatechange = alertContents;
	http_request.open('GET', url, true);
	http_request.send(null);
}

function alertContents() {
	if (http_request.readyState == 4) {
		if (http_request.status == 200) {
			var txt =  http_request.responseText;
			drawMarkers(txt);
		}
		else {
			//alert('There was a problem with the request.');
		}
	}
}